Recovery of Alkali from Bayer Red Mud Using CaO and/or MgO
AbstractRecovering alkali from Bayer red mud is crucial for storage security, resource utilization and environmental protection. In this study, the addition of MgO and/or CaO was conducted to recover alkali from red mud with a hydrothermal method for the first time. A synergistic result with a residual Na2O/SiO2 weight ratio of 0.03 was obtained by adding the blend of CaO and MgO at an appropriate temperature. MgO was found to be more temperature-dependent than CaO when substituting Na2O from red mud due to their different hydration processes. The alkali recovery was controlled by a reaction at a temperature of <200 °C and by internal diffusion at a higher temperature for MgO, but controlled by internal diffusion for CaO in the whole temperature range studied. The formation of hydrotalcite-like compounds with a loose structure was verified with the help of XRD, FTIR, and SEM-EDS. It was proved that both the reaction kinetics and the characteristics of solid products have a significant influence on the recovery of alkali. View Full-Text
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Zhou, B.; Cao, S.; Chen, F.; Zhang, F.; Zhang, Y. Recovery of Alkali from Bayer Red Mud Using CaO and/or MgO. Minerals 2019, 9, 269.
Zhou B, Cao S, Chen F, Zhang F, Zhang Y. Recovery of Alkali from Bayer Red Mud Using CaO and/or MgO. Minerals. 2019; 9(5):269.Chicago/Turabian Style
Zhou, Bingxin; Cao, Shaotao; Chen, Fangfang; Zhang, Fangfang; Zhang, Yi. 2019. "Recovery of Alkali from Bayer Red Mud Using CaO and/or MgO." Minerals 9, no. 5: 269.
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